Update src/int128_struct_impl.h

roconnor-blockstream · real-or-random · web-flow · commit 724d05f7206b · 2022-11-18T11:02:15.000-05:00
Co-authored-by: Tim Ruffing &lt;crypto@timruffing.de&gt;
diff --git a/src/int128_struct_impl.h b/src/int128_struct_impl.h
@@ -161,7 +161,7 @@ static SECP256K1_INLINE uint64_t secp256k1_i128_to_u64(const secp256k1_int128 *a
 
 static SECP256K1_INLINE int64_t secp256k1_i128_to_i64(const secp256k1_int128 *a) {
    /* Verify that a represents a 64 bit signed value by checking that the high bits are a sign extension of the low bits. */
-   VERIFY_CHECK(a->hi == -(uint64_t)(0x8000000000000000u == (0x8000000000000000u & a->lo)));
+   VERIFY_CHECK(a->hi == -(a->lo >> 63));
    return (int64_t)secp256k1_i128_to_u64(a);
 }
 

Original file line number	Diff line number	Diff line change
`@@ -161,7 +161,7 @@ static SECP256K1_INLINE uint64_t secp256k1_i128_to_u64(const secp256k1_int128 *a`
`161`	`161`
`162`	`162`	`static SECP256K1_INLINE int64_t secp256k1_i128_to_i64(const secp256k1_int128 *a) {`
`163`	`163`	`/* Verify that a represents a 64 bit signed value by checking that the high bits are a sign extension of the low bits. */`
`164`		`- VERIFY_CHECK(a->hi == -(uint64_t)(0x8000000000000000u == (0x8000000000000000u & a->lo)));`
	`164`	`+ VERIFY_CHECK(a->hi == -(a->lo >> 63));`
`165`	`165`	`return (int64_t)secp256k1_i128_to_u64(a);`
`166`	`166`	`}`
`167`	`167`